Apparatus and method for forming bullnose corner bead

Abstract

An portable apparatus for inexpensively forming plain angle ends of bullnose corner beading includes a base; an external die on the base; a pair of retainers for symmetrically holding opposite leg extremities of the corner bead relative to the external die; an internal die pivotally supported relative to the base for movement between open and closed positions for forming the end portion of the corner bead into the plain angular shape; a handle and link mechanism for operating the internal die; and a stop member rigidly located relative to the base for providing a predetermined length of the end portion. The retainers can be adjustable relative to the external die for accommodating corner bead having different flange widths, the retainers being movable symmetrically relative to a dihedral apex of the external die member. In another aspect of the invention, a method for forming the corner bead includes the steps of providing the corner bead having uniform bullnose cross-section; supporting the end portion of the corner bead against an external die; retaining opposite leg extremities of the corner bead in a laterally symmetric position relative to the external die; and driving an internal die into proximity with the exterior die whereby the planar surfaces of the interior die come into closely spaced relation to the external die over a predetermined distance for forming the end portion of the corner bead.

What is claimed is: 
     
       1. Apparatus for forming end portions of wide flange bullnose corner bead into a plain angular shape for a first distance from a corresponding end extremity of the corner bead, the corner bead being configured for use in building structures, the apparatus comprising: (a) a base;   (b) an external die rigidly supported by the base, the external die having planar surfaces intersecting at an exterior dihedral angle;   (c) a pair of retainer members extending within the dihedral angle in symmetrically spaced relation with the planar surfaces of the external die for holding the end portion of the corner bead with opposite leg extremities thereof in a laterally symmetric position relative to the external die, the corner bead contacting the planar surfaces thereof;   (d) an internal die member movably supported relative to the base for movement between open and closed positions in a plane bisecting the exterior dihedral angle, the internal die having planar surfaces intersecting an interior dihedral angle, the planar surfaces of the internal die being proximate the planar surfaces of the external die in the closed position for forming the end portion of the corner bead into the plain angular shape; and   (e) a driver for moving the internal die between the open and closed positions.   
     
     
       2. The apparatus of claim 1, wherein the external dihedral angle is approximately 90°. 
     
     
       3. The apparatus of claim 2, wherein the internal dihedral angle is approximately 90°. 
     
     
       4. The apparatus of claim 1, further comprising a stop member rigidly located relative to the base for providing a predetermined distance over which the internal die extends on the corner bead from the end extremity. 
     
     
       5. The apparatus of claim 1, further comprising a cradle rigidly supported relative to the base in spaced relation to the external die and in alignment therewith for supporting a portion of the corner bead during operation of the internal die. 
     
     
       6. The apparatus of claim 5, wherein the retainer members are primary retainer members, the primary retainer members being located proximate the external die, the apparatus further comprising a pair of secondary retainer members located proximate the cradle for holding a portion of the corner bead on the cradle and aligned with the external die. 
     
     
       7. The apparatus of claim 1, wherein the driver comprises an arm member pivotally mounted relative to the base, and a link pivotally connected between the arm member and the internal die. 
     
     
       8. The apparatus of claim 1, wherein the internal die is pivotally supported relative to the base on a die pivot axis. 
     
     
       9. The apparatus of claim 1, wherein the retainer members are adjustable relative to the external die for accommodating the corner bead having different flange widths, the retainer members being movable symmetrically relative to a dihedral apex of the external die member. 
     
     
       10. The apparatus of claim 9, wherein the retainer members are movable vertically relative to the base. 
     
     
       11. The apparatus of claim 9, wherein the retainer members are coupled for unison movement relative to the base. 
     
     
       12. Apparatus for forming end portions of wide flange bullnose corner bead into a plain angular shape for a first distance from a corresponding end extremity of the corner bead, the corner bead being configured for use in building structures, the apparatus comprising: (a) a base;   (b) an external die rigidly supported by the base, the external die having planar surfaces intersecting at an exterior dihedral angle of approximately 90°;   (c) a pair of retainer members extending within the dihedral angle in symmetrically spaced relation with the planar surfaces of the external die for holding the end portion of the corner bead with opposite leg extremities thereof in a laterally symmetric position relative to the external die, the corner bead contacting the planar surfaces thereof;   (d) an internal die member pivotally supported relative to the base on a die pivot axis for movement between open and closed positions in a plane bisecting the exterior dihedral angle, the internal die having planar surfaces intersecting an internal dihedral angle of approximately 90°, the planar surfaces of the internal die being proximate the planar surfaces of the external die in the closed position for forming the end portion of the corner bead into the plain angular shape;   (e) a driver for moving the internal die between the open and closed positions, the driver comprising an arm member pivotally mounted relative to the base, and a link pivotally connected between the arm member and the internal die;   (f) a stop member rigidly located relative to the base for providing a predetermined distance over which the internal die extends on the corner bead from the end extremity.   
     
     
       13. A method for preparing wide flange bullnose corner bead in a predetermined length for use in building structures wherein at least one end portion of the corner bead is required to have a plain angular shape for a first distance from a corresponding end extremity of the corner bead, comprising the steps of: (a) providing a member of the corner bead having uniform bullnose cross-section in the predetermined length;   (b) supporting external leg portions of the end portion of the corner bead against an external die having planar surfaces intersecting at an external dihedral angle;   (c) retaining opposite leg extremities of the corner bead proximate the end portion in a laterally symmetric position relative to the external die; and   (d) driving an internal die having planar surfaces intersecting at an interior dihedral angle in a direction bisecting the exterior dihedral angle into proximity with the exterior die whereby the planar surfaces of the interior die come into closely spaced relation to the external die over a predetermined distance not less than the first distance for forming the end portion of the corner bead.   
     
     
       14. The method of claim 13, including the further steps of: (a) providing a stop member for limiting the predetermined distance over which the internal die extends; and   (b) before the step of driving the die, positioning the end extremity of the corner bead against the stop member.   
     
     
       15. The method of claim 13, including the further steps of: (a) providing a cradle rigidly spaced from the external die and in alignment therewith for supporting a portion of the corner bead;   (b) providing a pair of retainer members in alignment with opposite sides of the cradle; and   (c) locating opposite leg extremities of the corner bead between the retainer members with the corner bead contacting the cradle for support of the corner bead in alignment with the external die.   
     
     
       16. The method of claim 13, wherein the external dihedral angle is approximately 90°. 
     
     
       17. The method of claim 16, wherein the internal dihedral angle is approximately 90°.